1. Field of the Invention
The present invention relates generally to digital video recording devices, and more particularly, to methods and apparatuses for digital video recording using pre-event/post-event buffering.
2. Description of the Related Art
Digital technology has allowed law enforcement agencies around the world to make audio and video recording an essential tool for protection against false and malicious claims, for prosecuting defendants, and for training. Digital video recording provides obvious benefits over analog (VCR tape-based) video recording systems in quality, storage and a variety of options, such as the ability to search and locate a particular scene within a recording segment.
As shown in FIG. 1, generally, a digital video recording device 106, in a law enforcement vehicle 110, is in communication with a video camera 120, a general purpose computer 107, which may be separate as shown or integrated with the digital video recording device 106 as one unit, an audio input device (not shown), and a storage medium, for example, a hard disk drive 105. Digital video recording device 106 may interface with triggering devices (e.g., siren, light bar, air bag, vibration sensor) and/or switches for triggering permanent recording of the video and audio data to the hard disk drive 105. The video camera 120 is generally mounted to capture video data out the front window of the vehicle 110. An audio input device (not shown) may, in any combination, be mounted in the vehicle 110, worn by an officer, and/or provided as an output of the vehicle's two-way radio.
Generally, audio and video data is transferred to a storage medium, such as hard disk drive 105. In operation, a trigger event activates the digital video recording device 106 and in this way, the video and audio data is captured and then written to a memory device, such as hard disk drive 105. The recorded video data may then be archived, for example, by transferring (uploading) the data to a network for archiving or removing the hard disk drive to which it is recorded. A common problem with such systems is balancing the availability of a finite amount of physical space for storage of captured video and audio in a hard disk drive of a moving vehicle with potentially large amounts of information which may need to be recorded over long periods of time.
One known approach for addressing this problem involves only activating the digital video recorder in response to specific triggering events, such as an opening of a door, turning on a siren and/or lights, or removing a gun from a rack. By only recording when particular events occur, such arrangements can reduce the amount of video information to be recorded.
However, such techniques are cumbersome and costly in many ways. Often, when an event has been recorded, it is found to be of no use to the enforcement agency after it has been stored in the physical space of a law enforcement vehicle. In addition, these required triggering events tend to ensure that the period of time after the ending of the event will not be recorded. Unfortunately, this subsequent period of time is often found to be of great interest when later analyzing the recorded information. Further, this method does not give a law enforcement officer an ability to choose and record only pertinent data needed to be saved to a hard disk drive after the triggering event is activated and disregard data that is found to be of no value.
Therefore, a need exists for an improved method and an apparatus for digital video recording.